Retrieving content from couchdb using CouchDB::Client

shivam99aa has asked for the wisdom of the Perl Monks concerning the following question:

I am able to create new documents using CouchDB::Client as well as able to verify if any doc is present. What i am not able to do is to retrieve the contents of any doc. The reason is i am not able to get the correct syntax which is to be used for it. I am not a perl genius so taking a look at the source code did not help me either.

 use warnings;
use CouchDB::Client;

my $c = CouchDB::Client->new(uri => 'http://127.0.0.1:5984/');
my $db = $c->newDB('test');
my $doc = $db->newDoc('12345', undef, {'foo'=>'bar'})->create;

if ($db->docExists('12345')){
    print "hello\n";
}

#my $doc=CouchDB::Client::Doc->new($db);
print $doc->retrieve('12345');
[download]

I am able to create document but then i need to comment that line on next run as this will give storage error. But after commenting i have no way to retrieve the doc as i have no object remaining. But this should not be the constraint as there should be a way to retrieve doc using the db object by giving id to it.

Comment on Retrieving content from couchdb using CouchDB::Client Download Code

Replies are listed 'Best First'.
Re: Retrieving content from couchdb using CouchDB::Client by ww (Archbishop) on Apr 23, 2015 at 14:26 UTC
After reading the doc for CouchDB::Client, the only thing I see that may be helpful is under "Internal Methods" (which has a note: "You will use these at your own risk" -- offering a technique to obtain Couch objects. But, perhaps documents for the DB engine will provide some clues. Have you read those (with a microscope?) Or, perhaps these results from a Google search (terms: "CouchDB rename document") will be helpful: Storing Documents - CouchDB: The Definitive Guide guide.couchdb.org/draft/documents.html Documents are CouchDB's central data structure. To best understand and use CouchDB, you need to think in documents. This chapter walks you though the ... CouchDB Document API - Apache Wiki https://wiki.apache.org/couchdb/HTTP_Doc... Apache Software Foundation Jun 5, 2013 - A CouchDB document is simply a JSON object. You can use any JSON structure with nesting. You can fetch the document's revision ... Document_Update_Handlers - Couchdb Wiki - Apache Wiki https://wiki.apache.org/couchdb/Document... Apache Software Foundation Apr 23, 2014 - The official documentation has moved to http://docs.couchdb.org ... When the request to an update handler includes a document ID in the URL, ... [CouchDB-user] rename document attachment - Grokbase grokbase.com › Groups › CouchDB › user › September 2009 Sep 3, 2009 - (4 replies) I have a simple html/javascript app that uploads an attachment to a document. However, once it is uploaded I want to rename it to a ... Spirit of the Monastery	[reply] [d/l]
Re: Retrieving content from couchdb using CouchDB::Client by GotToBTru (Prior) on Apr 23, 2015 at 14:15 UTC
Is there a way to determine if newDoc might have failed to create the document? What is the result of running the following? `use warnings; use CouchDB::Client; my $c = CouchDB::Client->new(uri => 'http://127.0.0.1:5984/'); my $db = $c->newDB('test'); my ($doc) if ($db->docExists('12345')) { print "hello\n"; } else { $doc = $db->newDoc('12345', undef, {'foo'=>'bar'})->create; } print $doc->retrieve('12345');` [download] Dum Spiro Spero	[reply] [d/l]
Re^2: Retrieving content from couchdb using CouchDB::Client by shivam99aa (Novice) on Apr 23, 2015 at 15:39 UTC
CouchDB::Client::Doc=HASH(0x240e8e8) This is what i get in return, my point is that i created a document and then i am able to get it since $doc object is present but if the doc is present already in couchdb and i want to retrieve it then what should be the procedure. If i run the same code again then doc is already present in couchdb so i get this as output. hello Can't call method "retrieve" on an undefined value at couch.pl line 15.	[reply]
Re^3: Retrieving content from couchdb using CouchDB::Client by GotToBTru (Prior) on Apr 23, 2015 at 16:00 UTC
Perhaps apply the retrieve method to the $db object? `if ($db->docExists('12345')) { print "hello\n"; $doc = $db->retrieve('12345'); } else { $doc = $db->newDoc('12345', undef, {'foo'=>'bar'})->create; }` [download] Dum Spiro Spero	[reply] [d/l]
Re^4: Retrieving content from couchdb using CouchDB::Client by shivam99aa (Novice) on Apr 23, 2015 at 18:14 UTC
Re: Retrieving content from couchdb using CouchDB::Client by SimonPratt (Friar) on Apr 24, 2015 at 14:12 UTC
`my $doc = $db->newDoc('12345', undef, {'foo'=>'bar'})->create;` - this creates a document and stores it into the DB in one line. This can only be done once, without having the DB generate an error and crap out - Expecting otherwise is only something you should do if you're working with MySQL. To create a new, blank document object that you can work with, try `my $doc = $db->newDoc();`, or you could even go so far as `my $doc = $db->newDoc->retrieve('12345');` UPDATE: To my mind this is counter-intuitive, as retrieving a document from the DB should be something you do to the DB, not to a document object	[reply] [d/l] [select]